The number of possible firing sequences, or possible crank configurations, has already been largely described in the relevant literature for internal combustion engines with small number of cylinders, i.e. up to six cylinders for inline engines, and up to 12 cylinders for V-type engines. With increasing number of cylinders, the number of possible combinations of firing sequences or crank stars grows disproportionately, however, while the vibration dynamics of the crankshaft and of the entire engine become much more complex at the same time. Therefore, the selection of a suitable crank star and firing sequence for multi-cylinder internal combustion engines requires a deep understanding of both the mechanics and the vibration dynamics as well as of the gas cycle dynamics. The systematic evaluation therefore requires computer-assisted simulation and optimizing methods.
There exist already a couple of patents on firing sequences. U.S. Pat. No. 2,740,389 deals with the effects of firing sequences on the air path in internal combustion engines having a plurality of cylinders. U.S. Pat. No. 7,979,193 deals with the firing sequences of a 12 cylinder internal combustion engine in V90° configuration. EP 1 793 104 B9 shows a number of advantageous firing sequences for a 15-cylinder internal combustion engine in inline configuration.
It is the object of the present invention to provide a V-type 20 cylinder four-stroke internal combustion engine with advantageous properties regarding the above-mentioned criteria.
This object is achieved in a first aspect by a V-type 4-stroke internal combustion engine having 20 cylinders, having a counter-clockwise or clockwise direction of rotation, comprising a crankshaft, a torsional vibration damper and a flywheel arranged on the crankshaft, wherein the crankshaft has 10 crank throws forming a crank star, wherein in each case the piston rods of the two cylinders of a V-segment are connected to the same crank throw, wherein the crank throws C1 to C10 have one of the following angular sequences in the direction of rotation of the engine when seen from the side of the flywheel, with the crank throws numbered as C1 to C10 when starting from the side of the flywheel:
i) C1, C9, C4, C6, C3, C10, C2, C7, C5, C8
ii) C1, C8, C5, C7, C2, C10, C3, C6, C4, C9
iii) C1, C9, C5, C7, C3, C10, C2, C6, C4, C8
iv) C1, C9, C7, C3, C6, C10, C2, C4, C8, C5
v) C1, C7, C5, C8, C2, C10, C4, C6, C3, C9
vi) C1, C9, C7, C3, C5, C10, C2, C4, C8, C6
vii) C1, C6, C8, C4, C2, C10, C5, C3, C7, C9
viii) C1, C5, C8, C4, C2, C10, C6, C3, C7, C9
ix) C1, C8, C4, C6, C2, C10, C3, C7, C5, C9. Advantageous embodiments of the present invention form the subject of the dependent claims.
The first aspect of the present invention relates to the configuration of the crank star of the four-stroke internal combustion engine, i.e. to the arrangement of the crank throws along the crankshaft.
According to the first aspect, the present invention comprises a V-type 4-stroke internal combustion engine having 20 cylinders, having a counter-clockwise or clockwise direction of rotation, comprising a crankshaft, a torsional vibration damper and a flywheel arranged on the crankshaft, wherein the crankshaft has 10 crank throws forming a crank star, wherein in each case the piston rods of the two cylinders of a V-segment are connected to the same crank throw, wherein the crank throws C1 to C10 have one of the following angular sequences in the direction of rotation of the engine when seen from the side of the flywheel, with the crank throws numbered as C1 to C10 when starting from the side of the flywheel:
i) C1, C9, C4, C6, C3, C10, C2, C7, C5, C8
ii) C1, C8, C5, C7, C2, C10, C3, C6, C4, C9
iii) C1, C9, C5, C7, C3, C10, C2, C6, C4, C8
iv) C1, C9, C7, C3, C6, C10, C2, C4, C8, C5
v) C1, C7, C5, C8, C2, C10, C4, C6, C3, C9
vi) C1, C9, C7, C3, C5, C10, C2, C4, C8, C6
vii) C1, C6, C8, C4, C2, C10, C5, C3, C7, C9
viii) C1, C5, C8, C4, C2, C10, C6, C3, C7, C9
ix) C1, C8, C4, C6, C2, C10, C3, C7, C5, C9.
Four-stroke internal combustion engines in a V configuration having 20 cylinders having such crank stars are not known from the prior art. The inventors of the present invention have taken into account that the design of the crank star and in particular the order of the individual crank throws along the crankshaft also have a substantial influence on the vibration dynamics of the crankshaft and of the engine. The inventors have determined, on the basis of a computer-assisted simulation and optimizing method and by a systematic evaluation of the mechanics and vibration dynamics relevant to the selection of a suitable crank star, those crank stars which have particularly good properties with respect to the vibration properties.
Independently of the configuration of the crank star of the four-stroke internal combustion engine according to the first aspect, i.e. to the arrangement of the crank throws along the crankshaft, the present invention relates in a second aspect to the firing sequences of a V-type 20 cylinder four-stroke internal combustion engine.
In the second aspect, the present invention deals with optimized firing sequences for a V-type 20 cylinder four-stroke internal combustion engine. Since the optimum firing sequences depend on the direction of rotation of the four-stroke internal combustion engine, this first aspect comprises two variations.
In a first variant of the second aspect, the present invention comprises a V-type 4-stroke internal combustion engine with 20 cylinders, having a counter-clockwise direction of rotation, comprising a firing sequence controller that fires the cylinders A1 to A10 and B1 to B10 in at least one of the following firing sequences, wherein the direction of rotation and the cylinder numbering is defined in accordance with DIN ISO 1204:
a) A1-A5-B2-A4-B6-B3-A6-B9-B1-A9-B8-B4-A8-B10-A2-A10-B7-A3-A7-B5
b) A1-B4-B2-A4-B6-B3-A6-B9-B1-A9-B8-A5-A8-B10-A2-A10-B7-A3-A7-B5
c) A1-A6-B2-A4-B5-B3-A5-B9-B1-A9-B8-B4-A8-B10-A2-A10-B7-A3-A7-B6
d) A1-B4-B2-A4-B5-B3-A5-B9-B1-A9-B8-A6-A8-B10-A2-A10-B7-A3-A7-B6
e) A1-A9-B5-A3-A5-B4-A2-A4-B1-A6-B7-B3-A7-B10-B2-A10-B8-B6-A8-B9
f) A1-A9-B6-A3-A6-B4-A2-A4-B1-A5-B7-B3-A7-B10-B2-A10-B8-B5-A8-B9
g) A1-A8-B2-A6-B3-A10-B5-A7-B1-A9-B4-B6-A4-B10-A2-B7-A3-B9-A5-B8
h) A1-A8-B2-A7-B3-A10-B4-A6-B1-A9-B5-B7-A5-B10-A2-B6-A3-B9-A4-B8
i) A1-B6-A4-B10-A3-B7-A2-B8-B1-A8-B4-A9-B3-A6-B2-A10-B5-A7-A5-B9
j) A1-B6-A3-B10-A4-B8-A2-A8-B1-A7-B3-A9-B4-A6-B2-A10-B5-B7-A5-B9
k) A1-B7-A5-B10-A3-B6-A2-B8-B1-A8-B5-A9-B3-A7-B2-A10-B4-A6-A4-B9
l) A1-A6-B2-B10-A2-A10-B7-B9-A7-A9-B8-B4-A8-A4-B5-B3-A5-A3-B1-B6
m) A1-A5-B2-B10-A2-A10-B7-B9-A7-A9-B8-B4-A8-A4-B6-B3-A6-A3-B1-B5
In a second variant of the second aspect, the present invention comprises a V-type 4-stroke internal combustion engine with 20 cylinders, having a clockwise direction of rotation, comprising a firing sequence controller that fires the cylinders A1 to A10 and B1 to B10 in at least one of the following firing sequences, wherein the direction of rotation and the cylinder numbering is defined in accordance with DIN ISO 1204:
B1-B5-A2-B4-A6-A3-B6-A9-A1-B9-A8-A4-B8-A10-B2-B10-A7-B3-B7-A5
B1-A4-A2-B4-A6-A3-B6-A9-A1-B9-A8-B5-B8-A10-B2-B10-A7-B3-B7-A5
B1-B6-A2-B4-A5-A3-B5-A9-A1-B9-A8-A4-B8-A10-B2-B10-A7-B3-B7-A6
B1-A4-A2-B4-A5-A3-B5-A9-A1-B9-A8-B6-B8-A10-B2-B10-A7-B3-B7-A6
B1-B9-A5-B3-B5-A4-B2-B4-A1-B6-A7-A3-B7-A10-A2-B10-A8-A6-B8-A9
B1-B9-A6-B3-B6-A4-B2-B4-A1-B5-A7-A3-B7-A10-A2-B10-A8-A5-B8-A9
B1-B8-A2-B6-A3-B10-A5-B7-A1-B9-A4-A6-B4-A10-B2-A7-B3-A9-B5-A8
B1-B8-A2-B7-A3-B10-A4-B6-A1-B9-A5-A7-B5-A10-B2-A6-B3-A9-B4-A8
B1-A6-B4-A10-B3-A7-B2-A8-A1-B8-A4-B9-A3-B6-A2-B10-A5-B7-B5-A9
B1-A6-B3-A10-B4-A8-B2-B8-A1-B7-A3-B9-A4-B6-A2-B10-A5-A7-B5-A9
B1-A7-B5-A10-B3-A6-B2-A8-A1-B8-A5-B9-A3-B7-A2-B10-A4-B6-B4-A9
B1-B6-A2-A10-B2-B10-A7-A9-B7-B9-A8-A4-B8-B4-A5-A3-B5-B3-A1-A6
B1-B5-A2-A10-B2-B10-A7-A9-B7-B9-A8-A4-B8-B4-A6-A3-B6-B3-A1-A5
The inventors of the present invention have arrived at these firing sequences on the basis of a computer-assisted simulation and optimization procedure, including a systematic evaluation of structural vibrations and gas cycle dynamics relevant to the selection of a suitable firing sequence for V20 internal combustion engines. The claimed firing sequences have particularly advantageous properties with respect to torsional vibrations of the crankshaft, gas cycle dynamics, load on the crankshaft main bearings and engine operational vibrations.
The fatigue strength and thus the service life of the engine are increased by the reduced load on the crankshaft and on the crankshaft bearings as well as by the reduction of engine operational vibrations. The construction effort for the engine and for the connection to further components can furthermore be reduced. In possible applications, due to the small torsion load on the crankshaft due to the optimized firing sequences, inexpensive crankshaft materials may be used. The reduction in the torsional vibrations can furthermore permit the use of a compact torsional vibration damper of a simple design. These aspects represent a substantial cost advantage in mass production.
In the four-stroke internal combustion engines in a V configuration having 20 cylinders of the second aspect of the present invention, the crankshaft has crank throws at which the connecting rods of the cylinders engage. Preferably, the connecting rods of the two cylinders of a V-segment of the four-stroke internal combustion engine share a common crank. The crank throws of the crankshaft, in their orientation along the crankshaft axis, form a so-called crank star.
The optimized firing sequences in accordance with the second aspect and the optimized crank stars in accordance with the first aspect form independently from each other the subject matter of the present invention.
However, in a preferred embodiment, the first and the second aspect are combined. In particular, the four-stroke internal combustion engines of the present invention are preferably operated with a crank star configured in accordance with the first aspect and with a firing sequence in accordance with the second aspect.
The following combinations of the crank stars and firing sequences discussed above are particularly preferred, both for V-type 4-stroke internal combustion engine having a clockwise and counter-clockwise direction of rotation:
crank star i), firing sequence h
crank star ii), firing sequence i
crank star iii), firing sequence g
crank star iv), one of the firing sequences a, b and m
crank star v), firing sequence j
crank star vi), one of the firing sequences c, d and l
crank star vii), firing sequence e
crank star viii), firing sequence f
crank star ix), firing sequence k
The inventors of the present invention have recognized that particularly good results can be achieved by these combinations of the crank star and firing sequence.
Preferred embodiments of the present invention, which can be used both with a four-stroke internal combustion engine in accordance with the first aspect, and with a four-stroke internal combustion engine in accordance with the second aspect, and with a combination of these aspects, will be explained in more detail in the following.
In embodiments of the present invention, the V angle of the four-stroke internal combustion engine can be chosen to be between 40° and 80°, more preferably between 50° and 70°, more preferably between 55° and 65°, most preferably at 60°. The inventors of the present invention have recognized that the V angle also has an influence on the above-named aspects to be optimized. There is furthermore a certain interaction between the firing sequences or crank stars and the V angle. In the present embodiment, the V angle is not optimized with respect to the firing behavior of the 20 cylinder engine, as it does not allow equidistant firing sequences. However, the V-angle is chosen such that it can be used for a whole range of engines having different numbers of cylinders, in order to keep production costs low.
The crankshaft has 10 crank throws at which the connecting rods of the cylinders engage, with the connecting rods of the two cylinders of a V-segment of the four-stroke internal combustion engine each sharing a common crank throw. The crank throws form a crank star.
In a preferred embodiment, a simple crank star is used for the engines of the present invention, i.e. a crank star where all the crank throws have a different angular position. This is contrary to conventional engine design, which makes use of a symmetric crankshaft formed by two symmetric halves. While such symmetric crankshafts have advantages with respect to free moments of accelerated masses, the inventors of the present invention have found that a simple or asymmetric crank star will be more advantageous if all aspects of the optimization are taken into account.
In a preferred embodiment, the crank throws are arranged on the crank star with an intermediate angle of n*36°±5°, preferably of n*36°±3°, more preferably of n*36°±1°, wherein n is a different integer between 1 and 9 for each crank star. The crank throws are therefore arranged equidistantly or at least quasi-equidistantly on the crankshaft.
The present invention preferably uses firing sequences where the angular distances between to firings are not too far away from each other. This is easier to accomplish with an asymmetric crank shaft, which therefore allows to improve the regularity of the firing intervals.
In a preferred embodiment, the firing sequences have an angular firing distance for two cylinders of the same bank between 26° and 46°, preferably between 31° and 41°, most preferably at 36°. The firing sequences have, for the counter-clockwise direction of rotation, an angular firing distance for a firing of a cylinder of the A-bank followed by a firing of a cylinder of the B-bank of between 38° and 58°, preferably between 43° and 53°, most preferably at 48° and/or for a firing of a cylinder of the B-bank followed by a firing of a cylinder of the A-bank of between 14° and 34°, preferably between 19° and 29°, most preferably at 24°.
For the clockwise direction of rotation, the firing sequences preferably have an angular firing distance for a firing of a cylinder of the B-bank followed by a firing of a cylinder of the A-bank of between 38° and 58°, preferably between 43° and 53°, most preferably at 48°, and/or for a firing of a cylinder of the A-bank followed by a firing of a cylinder of the B-bank of between 14° and 34°, preferably between 19° and 29°, most preferably at 24°.
The four-stroke internal combustion engine in accordance with the invention preferably has a torsional vibration damper which damps the torsional vibrations of the crankshaft. Because an engine according to the present invention will have lower torsional vibrations, the required power loss of the torsional vibration damper can equally be reduced with respect to known four-stroke internal combustion engines.
The power loss of the torsional vibration damper preferably amounts to less than 3 per mil of the maximum engine power; further preferably to less than 2 per mil; further preferably to less than 1.5 per mil; and further preferably to less than 1 per mil of the maximum engine power. It is additionally possible due to the required power loss of the torsional vibration damper reduced in accordance with the invention to use favorable and technically less complex vibration dampers.
Due to the reduction of the power loss of the torsional vibration damper, the present invention makes it possible to use technically less complex vibration dampers.
In accordance with an aspect of the invention, a viscous damper is used. Such a damper is substantially less expensive than a leaf spring damper. The use of a leaf spring damper remains of course possible for engines of the present invention depending on the application purpose.
The four-stroke internal combustion engine in accordance with the invention has a crankshaft and a flywheel arranged on the crankshaft. The power take-off preferably takes place at the side of the flywheel, which is typically connected directly or via a coupling to a shaft which drives a load. The torsional vibration damper is preferably arranged at the free side of the crankshaft disposed opposite the flywheel. The torsional vibration damper is particularly preferably arranged outside the engine casing.
Four-stroke internal combustion engines in accordance with the present invention can be used in a plurality of different configurations and dimensions.
In a possible embodiment of the present invention, the displacement volume per cylinder is between 1 l and 20 l, preferably between 1.5 l and 15 l, more preferably between 2 l and 9 l.
In a possible embodiment of the present invention, the maximum engine power per liter displacement volume is between 10 kW and 100 kW, preferably between 20 kW and 70 kW.
In a possible embodiment of the present invention, the engine has an operating speed range of between 600 and 2100 rpm. The speed range of a specific four-stroke internal combustion engine in accordance with the invention actually used for an application can make up a part range of this speed range.
In a possible embodiment of the present invention, the engine has an engine controller programmed to run the engine at a constant nominal operating speed, wherein the constant nominal operating speed preferably can be adapted based on engine conditions and/or load conditions, and/or wherein the constant nominal operating speed preferably is from an operating speed range between 600 and 2100 rpm.
In particular, the engine is preferably controlled such that the engine again reaches the nominal engine speed after brief load changes which allow the actual engine speed to deviate from the nominal engine speed. In a possible embodiment, the nominal engine speed can be kept constant. The nominal engine speed is in particular kept constant over time periods which are long with respect to the typical load changes. In accordance with the invention, the engine control can, however, be designed such that the nominal engine speed can be adapted to changing engine conditions and/or load conditions.
The engine in accordance with the invention can, however, also be operated using any desired other engine control principles.
In possible embodiments of the present invention, the engine is operable with a gaseous and/or with a liquid fuel, wherein the engine can preferably be operated with at least one of the following fuels: gas, diesel, gasoline.
The engine in accordance with the invention can be a gas engine. In this case, the engine is operable with a gaseous fuel such as hydrogen, natural gas, biogas and/or liquefied gas.
Alternatively or additionally, the engine can also be operable with a liquid fuel. The engine can, for example, be operable with diesel and/or gasoline.
In a possible embodiment, the engine in accordance with the invention can only be operable only with a gaseous fuel or only with a liquid fuel. Alternatively, an operation with both a gaseous fuel and with a liquid fuel is possible.
In possible embodiments of the present invention, the engine has a direct injection system and/or a high pressure injection system. Such injection systems are particularly preferably used with an engine which is operable with liquid fuel.
In possible embodiments of the present invention, the engine can be operated with a Diesel or an Otto combustion process.
In possible embodiments of the present invention, the engine controller is programmed to operate the engine with a homogeneous charge and/or stratified charge combustion method. In possible applications, one out of several available combustion methods can be used in dependence on the engine conditions and/or load conditions.
In a possible embodiment of the present invention, the engine is a suction engine. Alternatively, the engine may be equipped with a boosting system with one or several stages. The engine can in particular have one or more turbochargers and/or compressors.
In a preferred embodiment of the present invention, all cylinders of one cylinder bank have a common intake manifold and/or a common exhaust manifold, wherein the exhaust manifolds are preferably arranged with respect to the V-angle on the inside and the intake manifolds are arranged with respect to the V-angle on the outside.
The engine of the present invention can be used in a multitude of different applications:
In a possible application, the engine is used as a power unit in a heavy duty and/or mining and/or earth moving and/or transport and/or cargo and/or load handling machine, preferably for an excavator and/or a dumper truck.
In a possible application, the engine is used to run a generator and/or a hydraulic pump, the generator and/or the hydraulic pump preferably operating one or more drives of an undercarriage and/or working equipment, preferably of a heavy duty and/or mining and/or earth moving and/or transport and/or cargo and/or load handling machine, preferably for an excavator and/or an dumper truck.
In a possible application, the engine is coupled directly or via a mechanical gear train to an undercarriage and/or working equipment, preferably of a heavy duty and/or mining and/or earth moving and/or transport and/or cargo and/or load handling machine, preferably for an excavator and/or a dumper truck.
In a possible application, the engine is used as the main power unit for a ship. In this case, the crankshaft preferably drives the propeller of the ship. The shaft of the propeller can be connected to the flywheel of the engine directly or via a clutch and/or a transmission.
In a possible application, the engine is used as the main power unit for a train. In this case, the engine preferably drives a generator. The rail vehicle can in particular be operated diesel electrically. Alternatively, the drive can take place via a transmission which is preferably connected to the engine by means of a clutch and/or a torque converter.
In a possible application, the engine is used as a power unit in military equipment. The engine can in particular be used in an armored vehicle and/or in a rocket carrier and/or in a speedboat and/or in a submarine.
The engine in accordance with the invention can furthermore be used as a drive for fluid transport and/or for gas and/or fuel production and/or treatment. For example, the engine can be used as the drive of a pump and/or of an oil and/or gas extraction machine, of an oil and/or gas transporting machine and/or of an oil and/or gas processing machine.
In a possible application, the engine is used as a power unit for power generation, an in particular drives a generator. The engine can be used for stationary or mobile power generation.
In a possible application, the engine is used as a power unit for a mobile and/or stationary machine.
In a possible application, the load can be connected to the crankshaft in a torsionally rigid manner. Alternatively, the load can, however, also be connected to the crankshaft via a torsionally flexible coupling. Such a torsionally flexible coupling absorbs torsional vibrations to a certain extent and thus reduces the transmission of still present torsional vibrations of the crankshaft to the driven load.
The present invention further comprises a machine comprising a V-type 4-stroke internal combustion engine as described above. The engine of the present invention may in particular be used to drive the machine or a piece of working equipment of the machine.
In particular, the machine may be a stationary or a mobile machine.
The machine in accordance with the invention is in particular one of the above-named applications. The machine in accordance with the invention can, for example, be a heavy duty and/or mining and/or earth moving and/or transport and/or cargo and/or load handling machine, and/or a ship and/or a train and/or a military and/or fluid transport and/or gas and/or oil production and/or treatment machine and/or a power generator. Preferably, the machine is an excavator and/or a dumper truck.
The present invention further comprises a firing sequence controller or a software for a V-type 4-stroke internal combustion engine with 20 cylinders, in particular for a V-type 4-stroke internal combustion engine as described above, the firing sequence controller or software implementing at least one of the firing sequences provided above with respect to the second aspect. In the firing sequence controller of the present invention, the firing sequence may be predefined by the constructional design of the engine, for example by a firing sequence controller driven mechanically via a camshaft. Preferably, the firing sequence controller comprises an electronic controller programmed to control the engine with one of the inventive firing sequences.
The present invention further comprises a method for operating a V-type 4-stroke internal combustion engine with 20 cylinders, in particular a V-type 4-stroke internal combustion engine as described above, wherein the engine is operated with at least one out of the firing sequences provided above with respect to the second aspect.
The design of a four-stroke reciprocating internal combustion engine having 20 cylinders in accordance with the invention is shown schematically in FIGS. 1 to 3.